Carburetor for internal combustion engines



Jan. 10, 1933. c. P. NEWBERRY 1,893,550

CARBURETOR FOR INTERNAL: COMBUSTION ENGINES a w A1, A b c I m 1" V a 2 i ATTORNEYS Patented Jan. 10, 1933 UNITED STATES PATENT OFFICE CHARLES PETER NEWIBERRY, OF- TWEESPRUIT, ORANGE FREE STATE, UNION OF SOUTH AFRICA CARBURETOR FOR INTERNAL COTMBUSTION ENGINES App1ication filed October 22, 192?, Serial No. 228,044,

This invention relates to a new or improved carburetor and has for its object to provide an adjunct to petrol engines which shall be capable of efliciently and rapidly atomizing the liquid fuel and combining it with air to ensure the engine receiving an explosive mlxture of greater efliciency than has heretofore been obtainable, due to improved carburation.

In accordance with my invention I provide a stream-lined valve or plunger which slides vertically and concentrically in a Venturi type choke tube of lesser diameter than the valve or plunger. It completely closes the tube when it is in its lowest position and leaves a passage for the gas equal to or greater than the valve opening of the engine concerned, when in its raised position.

The stem of this valve is hollow, and dips into a float chamber situated below the concentric to the choke tube and valve, the petrol level being maintained by a float, lever and ball valve of the customary type.

Ports for the ingress of air are arranged between the choke tube and the float chamber, giving a symmetrical and stream-lined entrance for the air. At the upper end of the stem is situated a nozzle above which is a small passage connecting with a circumferential slot in the periphery of the valve head immediately above that portion which seats against the inside of the choke tube. A needle with tapered point is fitted centrally through the bottom of the float chamber and is adjustable vertically, the tapered point extending through the nozzle. When the valve is in ts lowest position shutting oil? the air entirely, the needle is adjusted vertically, so as to close or nearly close the jet.

As the valve is raised, admitting more air the nozzle is withdrawn up the tapered needle admitting more petrol, and the angle of this taper is predetermined with a View to keeping the proportion of petrol to air constant at the correct ratio. The valve is raised by means of a rack and pinion, the latter being on a spindle at right angles to and tangential to the stem of the valve on which the rack is out.

In order that my invention may be readily understood and carried into practice refand in the Union of South Africa September 15, 1927.

erence is hereby made to the accompanying sheet of drawing wherein Fig. 1 is a sectional view and Fig. 2 is a part elevation of the lower portion of the same having portions cut away to more clearly illustrate the construction' 'Referring to the drawing wherein like letters of reference indicate corresponding parts wherever occurring throughout all the figures, a designates the stream-lined valve or plunger which slides in the choke tube 7), indicates the hollow stem of the valve a which slides in the axial bore a of the operative member I), said-member constituting a closure for the float chamber (Z' wherein are also situated the float e, the lever f and the ball valve 9. It will be noted that the stem depends into the float chamber and extends through the float. At the upper end of the stem 0 is situated a jet it above which is a small passage connecting with the circumferential slot j. Through the jet it extends a tapered needle k. On the lower part of the stem 0 is cut a rack Z and engaging it is a pinion m mounted ona spindle n operated by the crank 0. In the walls of the tube are cut ports 79 opening at points above member Z) for the ingress of air while petrol is admitted at the inlet 9. A chamber r is provided in the member 5 for the assembly of the pinion m on the spindle n and this is made dustproof by the cover 8.

The stream-lined valve or plunger 0 slides vertically and concentrically in the Venturi type choke tube 6 of lesser internal diameter than the valve a. It completely closes the choke tube when it is in its lowest position, and leaves a passage for the gases equal to or greater than the valve opening of the engine concerned, when in its raised position.

The stem 0 of the valve is hollow, and extends into the float chamber d, situated below, and concentric to the choke tube and valve, the petrol level being maintained by a single float e, lever f and ball valve The ports 39 for the ingress of air are arranged between the choke tube and the float chamber, giving a symmetrical and streamlined entrance for the air.

of the invention,

At the upper end of the stem 0 is situated a jet h, above which is a small passage connecting with a circumferential slot j, in the periphery of the valve head. This slot is at the maximum diameter of the valve head, immediately above that portion which seats against the inside of the choke tube.

The needle with a tapered point is fitted centrally through the bottom of the float chamber and is adjustable vertically and the tapered point extends through the jet h. When the valve a is in its lowest position, shutting off the air entirely, the needle is adjusted vertically, so as to close, or nearly close, the jet.

As the valve is raised, admitting more air, the jet is withdrawn up the tapered needle, admitting more petrol, and the angle of this taper is determined so as to keep the proportion of petrol to air constant at the correct ratio.

The valve a is raised by means of a rack Z and pinion m, the pinion being on a spindle at right angles to, and tangential to, the stem of the valve, on which the rack is out.

A choke tube may be used which has a minimum internal cross-section not less than the valve opening of the engine concerned without prejudicing the efficiency at lower engine speeds, thus allowing the maximum speed the engine is capable of.

The petrol, emerging from the jet which is in the axis of the valve, is drawn evenly outwards radially; it has thus to spread itself evenly over a very much larger space than it formerly occupied, being atomized in the process. At the moment of its emergence from the slot y, it is struck by a powerful air blast (at all throttle openings) thus completing the atomization.

The metering needle, in conjunction with the stream-lined valve insures a perfectly proportioned ratio of petrol to air through out the throttle range.

All of the gas passages are stream-lined so as to prevent eddies and a carburetor for large engines can be fitted to smaller ones without re-adjustment.

The carburetor may be adjusted to give a richer or leaner mixture without leaving the drivers seat.

What I claim is A carburetor comprising a casing having a Venturi tube therein, the contracted part of which constitutes a valve seat, a streamline valve adapted to slide coaxially in said tube, said valve having a greater diameter than the minor internal diameter of the tube, a hollow stem on said valve depending into the fuel reservoir of the carburetor, a partition member in the casing constituting a top closure for the float chamber, said member having a bore for slidably receiving said stem, an annular seating face on said valve immediately below its maximum diameter,

said valve being provided with an annular fuel orifice disposed above the seating face thereof, a fuel nozzle in the lower portion of said valve, air inlet ports formed in the easing and opening above the member, a tapered needle valve passable through the reservoir and stem, said member having a chamber therein, and means in the chamber for relatively adjusting the stem and needle valve. In testimony whereof I have afiixed my signature this 16th day of September, 1927. CHARLES PETER NEWBERRY. 

